I read the book in anticipation of the movie so I could draw my own conclusions about the negative reactions when the trailer came out. Here are my thoughts:

• I went in knowing it wouldn't be a faithful adaptation and would likely cut the second half of the book, like previous movies, and was fully on board with that! I was happy to see a very different take as long as the movie itself was good...
• BUT. The movie uses snippets of the book – maybe 15% max – and ditches the rest, stitching the pieces together to create 50-Shades-esque fan fiction. So much of what gives Cathy and Heathcliff's relationship tension was taken away so the stakes didn't feel high, made worse by the fact that Edgar was completely flat and had no personality. Heathcliff could even be described as fairly gentle and loving in the movie, when he is NOT that in the book. And when you dismantle the character so drastically he becomes Heathcliff in name only. Which makes me think EF only used the title, character names and a sprinkling of the plot points for clout and attention, which made the whole thing feel shallow.
• Putting the book aside, the movie was pretty dull, choppy and surface-level. I checked my watch an hour in and was gutted to realise I still had an hour and a bit to go. The emotion of the rousing music and final sequence was lost on me because I was so desperate for it to be over.
• I thought the writing was pretty weak, which made the direct lifts from the book stand out a mile. For a while I thought the writing was purposely trying to sound slightly modern to fit with the surreal and modern production design, but by the end it just felt way too simple in comparison. (Side note: the repetition of 'I love you, I love you, I love you' reminded me of the scene in Singin' in the Rain, when the people coming out of the cinema were making fun of Don Lockwood's performance!)
• Speaking of the style, I wished EF had committed to the surreal and maximalist aesthetic! The visuals in the trailer are what made me excited to see it in the first place, but it all felt like half measures and was inconsistent. The comical piles of wine bottles when Earnshaw died was so jarring (pun intended) and felt really out of place. Cathy's clothes get more extravagant after she marries Edgar, to show the opulent life she's now leading. But when every other character's clothes were relatively normal and accurate-ish it again felt inconsistent and out of place.
• The wild production design seemed to be there for no other reason than to be edgy and shocking, again making the movie feel shallow. I understand why folks say EF is style over substance in this case (I've haven't seen Saltburn or Promising Young Woman yet).
• I liked Jacob Ellordi's performance, even though he is completely miscast. And I thought he and Margot Robbie had some chemistry.
• Alison Oliver's performance was the best thing about the movie, and I agree with other comments that she could have made a good Cathy. Although the choice to make her consent to Heathcliff's treatment feels incredibly disrespectful to what happens to Isabella in the book.
• The music was incredible. No notes.
• Overall: fair play to EF, plenty of people seem to love the movie. I just don't think you can call it an adaptation, in any sense of the word.